Hi, I have a 1.5-3v dc motor, and I am using a SN754410 to control them. The problem is that when I hook up 1 motor with a 3v power supply(2 AA batteries), the motor does not move but it makes a tiny noise when I put it near my ear. (I thought the motor no longer worked, but then I used 2 motors with a 6v power supply, and the motors ran at full speed.) Any help clearing this up for me? thanks.

Why oh why do people persist in using ancient bipolar H-bridge chips such as L293, L298 and SN754410? These chips have high voltage drop, which also means that they get hot and can't take much current. My advice is to forget bipolar motor driver chips and use modern mosfet-based chips instead. If you really want to use a bipolar chip, then read the datasheet to see how much voltage drop it has, and increase the power supply voltage over and above the motor voltage by that amount.

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The reason you'r hearing that noise is because your not giving the motor enough voltage. Due to the fact that your AA batteries probably are not really 1.5v more like 1.2v and because of the voltage drop due to The SN754410 your motors are not getting enough voltage. When you use the 6v your motors are getting plenty of voltage (probably to much). Keep in mind that voltage is not split up between the motors like amperage is. Each one is getting 6v. I would recommend using 3 AA batters. After voltage drop your motors should each get around 3V.

Why oh why do people persist in using ancient bipolar H-bridge chips such as L293, L298 and SN754410? These chips have high voltage drop, which also means that they get hot and can't take much current.

Probably because they are cheap, easy to obtain, come in thru-hole packages, and are well documented with tons of example designs; in other words, they have real "staying power". The L293/SN74410 works great for most hobby designs at 1 amp per channel (perfect for most small DC motors); the L298 is good for 2 amps per channel, or 4 amps in bridged mode (granted, you need one helluva heatsink for it, though). Even though they aren't the most efficient, for most hobby purposes, both work well.

Used right - the L293 can even be used as a driver for a MOSFET h-bridge (or a larger bipolar bridge)...

My advice is to forget bipolar motor driver chips and use modern mosfet-based chips instead.

If you have links to a good replacement MOSFET-based h-bridge driver chip in a thru-hole package variant that compare to the aforementioned bipolar devices, please post a link or some part numbers - I'm sure that tons of people would appreciate it!

If you have links to a good replacement MOSFET-based h-bridge driver chip in a thru-hole package variant that compare to the aforementioned bipolar devices, please post a link or some part numbers - I'm sure that tons of people would appreciate it!

Hey Drew, right now, i'm building a tank that will just move forward and turn for certain periods of time. Then im planning on hooking up a simple claw so it can pick up random things like a bottle of water...thanks for asking!